The present invention relates to a control apparatus of an engine with electromagnetically driven intake and exhaust valves and more particularly, to an engine control apparatus with electromagnetically driven intake and exhaust valves which can provide a wide dynamic range of engine brake torque even during fuel cut by controlling the valve open timing of the electromagnetically driven exhaust valve.
A technique disclosed in, for example, JP-A-63-147957 has hitherto been known in which by changing the valve timing of an electromagnetically driven valve, the engine brake effect can be obtained and the torque shock and pumping loss can be decreased. More particularly, in the technique, the valve timing of the intake valve is set to normal timing during deceleration fuel cut and is switched to the early close timing immediately before the fuel cut ends, that is, fuel supply is resumed.
However, the valve switching timing described in the conventional technique as above is set to two stages of normal timing and early close timing and therefore, when the early close timing always proceeds during the fuel cut, the pumping loss is decreased excessively to raise a disadvantage that the engine brake effect becomes insufficient.
Then, a technique has been proposed in JP-A-9-88645, according to which the valve open timing of the intake valve is controlled more finely under a predetermined running condition for fuel cut, thereby decreasing the pumping loss and providing suitable engine brake.